An international animal rights group called on Sri Lanka's separatist Tamil Tigers to "leave animals out" of the armed conflict, two weeks after a grenade attack blamed on rebels at the island's main zoo.

People for the Ethical Treatment of Animals, or PETA, said in a letter dated Feb. 15 to Velupillai Prabhakaran, the reclusive rebel leader, that "the explosive device that was set off near the zoo's bird enclosures terrified many animals at the zoo."

PETA president Ingrid E. Newkirk pleaded with the rebel leader "to leave animals out of this conflict," the letter said.

Newkirk added that the group has been inundated by messages from people saddened by the attack.

There was no immediate comment from rebels to the PETA's letter.